High-pressure locomotive



June 17, 1930. 1A, w, BRA DT 1,764,431

' PRESSURE LOCOMOTIVE Filed Jan. 24, 1925 3 Sheets-Sheet l C'AEL./7.NEH/V177:

INVENTOR.

.A TTORNEY.

June 11, 1930.

C. A. W. BRANDT HIGH PRESSURE LOCOMOTIVE Filed Jan. 24, 1925 5Sheetsheet 2 ATTORNEY.

June 17, 1930. c. A. w. BRANDT HIGH PRESSURE LOGOMOTIVE 3 Sheets-Sheet 3Filed Janv 24, 1925 I N VEN TOR.

CARL. A. W .BF/INDT BY Q/' A TTORNE Y.

it Patented June 17, 1930 tourney, ion-unw v nn N; Y.

' H ete momm- Application filed January 24 11925; s rierm. 4;5,4.5f T

'1 I l invention-relates .to locomotive boilers, r i particulanly-to thetypeiadapted to operate (at high puessures, although it is to beJlIldSQI- etoodithat :the @present invention is equally applicableinboilers to be operated at-eny de'sired pressure.

In meeting the demands for greater-locomotive boiler icapacity',,-thezlimit oifsize im- {posed by bridge and tunnel clearaneesqhasalreadyubeen reached. The, limit has 3150 been arrived at for safe'vvorkingpressunes iniexisting types of ;bqilers,and further. ca-

v aeit y per unit has been soughtiby-theaddi "uoannotmeet. Y i, i v Theobject. of I jy present :IILVGILHOH 1 s, I

ere, vfeed water .;heaters' .and th lik Whi h,

ab-1e, and the repidly inereasing co 9 fuel efficiency as vvell, which:present' loc motives therefore,itheprovision of a eilerei wh Vi byitheanrangement and distribntion o f the heating surfaces of the boiler in5119b meninert-as to secure the meet edva'ntegeeusze r- ,eulation.of'nwater throughout the boiler, and -.the most eifeetive heat transfethem th Hoo nbustion 'gases t the ee tentsiof the :heilin accordancewith the wel known conne-tenflow rineiple-Qf heat tnansvfer; A fu therobject of my invention is the p evision -.;o f-a aboiler which, by theelimination of all 'stayer surfaces, :is capable o ib ingepe ted atpressures of from 600 to $800 lbs. per

square inch 1 or even higher, and which thereby provides the advantagesto be deemed fuomzthe uselof high pree u es eem- Qth section ofapreferred form f myinventieni gene further objects will appear mo e fuly in connection with the following detailed i descniption of specificembedimen s of :my 7 a ,45

invention; which are illustrated in the aceompanying drawings, of whieh;

mFig. 1 is a longitudnal =vert alveent a1' I takenaontheline 1 1iof.:Fig,2, aportion of the figure being shown in nlevatl QIlividing arapid and Well defined wate irii i Fig. avertical transversesectionitaken ii V J "onthe line:2 ng2iof-Fig.-l;

.Fig; B ie a vertical transverse sectiontaken a 1011 the line=3 -.3.iofFig; ;1;; i Fig. 4 isa view similar to Fig; l ."of a asmodified form ofmy invention;

heath. w." Bnerrnr, gunmen esteem 03K, AS$IGNOR :Fig; 5' is a cQm-positevertical transverse section; the left Ehalfof which-is taken ton theline 5- 75 of Figs. lfandfltan'd thetright .half of which is taken onthe line fi r fi f of Figs, 1 and-4c;

Fig. 6' is a compositeaverticaltransverse section, the-left haif'ofwhich is takenfonthe line G -650i? Figs. 1 and hand the right Fig. .7 isa compQsite vertioal ltr ansvense section, the left halfof whiehxisltaken on y of whichis taken 4; and

Fig.:811s a viewawinie levationof a atten 'ofthe structures'hown inFig. 1. i

Asmay be-seen by aninspectwn'ofa-Fig; 1 1 4 l, I have divided the,heating surfaceof the,

boiler into ,fourgunits, consisting of a water ube imit f r-ridinga'fnrnaceand combustion ghamber, a, fire tube evaporating n lQQatQspaced theretrom, a :superheater unit located in the space @previdedbetween vthe two uni s j t ention d, and an ,ecenomizer un t 110 lhesection fo m ng ithe'fi eh xl nd-Com foiwvai'dly, of, said water tubelinitQand' reated f erwe dl y otsaid zfire tube e apq 1 bustien chamberof the. f:bbiler reselnbles in 3 I geneuelzferm the cross 'drumi ypeyofstatiQn-- ary boiler with the "central tubesiremovedj therefrom-andeliminat st e fi t ey dlsu "faces usual. in :thelerd lna y form o110.061 metive fire box se tion substituting herefor a tubefa dheader'eonstructien,ad pteditozbe 'safe ywperated atehigh pressur end,prov culationl Within the unit,

The a side Walls o his innit a e horizontally inclined tlibes, 1 offcornpara tively. large diameter; onta ting: t or 'i .a solid watercooled wal1. Attheir ends these tubes are swaged down to agsniallergltical headers 3 by a series of top and bot-- the unit and correspondingrear headers t (Figure 3) forming the outer extremities of the rearwallof the unit. This construction further permits sufiicient spacing ofthe tube holes in the headers 3 and 4 to give adequate ligamentstrengthfor the pressures contemplated. The roof is formed by a plurality ofspaced inclined roof tubes 5 supporting a refractory baflie of anydesired form which serves to close the space between the tubes, thetubes being similar in form to the tubes comprising the side wallsexcept for the fact they are bent, as at 7, to provide a shorthorizontal section in front of the rear header for a purpose to bereferred to later.

The rooftubes 5 are secured at their forwards ends to a horizontaltransverse header 8 and at their rearward ends to vertical headers 9which form the central portion of the rear wall of the unit. The rearvertical headers 4 and 9 are nippled attheir upper ends into atransverse header 10, and at their lower ends the outer headers 9 arenippled into a second transverse header 11 which is in turn nippled tothe inner side of the headers 4. The central headers 9 are shorter thanthe headers 9 and at their lower ends are nippled to a short transverseheader 12, which is nippled to the inner side of the two inner headers9, the

space between headers 11 and 12 and between the headers 9 providing afire opening 13.

The forward wall of the unit is formed by a series of short verticalheaders 14, which are connected to eachother and to the vertomtransverse nipples, and the transverse header 8, which is supported bythe headers 3 to which it is connected by end nipples. The space 15between the upper ends of headers l and the transverse header 8 ,formsan outlet for the combustion gases.

' which serves to direct the A transverse steam and water drum 18 ismounted above and parallel to the header 8 and is connected thereto andto the headers 3 by a plurality of nipples 19. The rear transverseheader 10 extends, as shown in- Figure 1, above the level'of the roofbattle 6 and is connected to the drum l8 by horizontal circulating tubes20, which are rolled or otherwise suitably secured in the drunr 18 atapproximately its horizontal diameter,

at which point the water level is normally carried.- 7

tubes 1 is placed in the same horizontal plane as the roof tubes,andformsa support for the outer portion of the roof baflie '6. Thetubes, 1 cannot be carried rearward beyond the point where the rooftubes are bent, inasmuch as the tubes l lie in the same vertical planewith the outermost circulating tubes 20 and at this point are directlybeneath them. Inorder therefore to accommodate these tubes the outercirculating tubes 20 instead of being integral lengths leg portionswhichreceive the rear ends of the tubes 1, the tube section 2O providing thenecessary communication between the tubes 1" and the header 10.

For the sake of'clearness the fuel grate has been omitted from thedrawing, and it will further be obvious that any desired form of fuelmay be utilized with equal facility,

- the ignited combustion gasespassing upward and rearwardly of the bafile 17 between the extended portion of the arch tubes 16, and thenforwardly to' the'combustion gas outlet 15. It is to be understood,however, that the form of bafitling may be altered in any way desiredtosuit specific individual requirements without departing from the spiritor scope of my invention.

By means of the construction just described I provide a fire box andcombustion space which presents substantially entirely water cooledsurfaces tojthe fire on all sides,

whereby a maximum amount of heat is absorbed by radiation, and this isaccomplished by means which entirely eliminate undes1rable flat stayedsurfaces and which follow only approved engineering practice. The tubesand drums maybe made of seamless V tubing, and the headers arepreferably of forged or cast steel, the entire structure be ing capableof withstandingextreme operating pressures.

Inasmuch as the major amount of evaporation takes place in this unit, itis imperative that there be a free, definite and regular watercirculation therein, and it will be obvious from Figure 1 that I haveprovided such; a circulation in which the forward headers 3 and nipples19 function as downcomers receiving water from drum 18 and supplying theevaporating side, roof, and

uptake headers 4 and 9. The discharge from the up-take headersisreceived by the cirarch-tubes, which dischargeinto the rear ,55fexposure of riigete i 'icnlating tubes 20 through the upper TICK/3J1tra'nsi er selheader IOQnd'these-tuheS together W t -.1 e 1 dri i a pr ie; e e s t steam disengagingsurfacefor the separation of therstealnandwater discharged. 'froinithe .eyaponatingjtubes, Itwill thusbe seen that I :liaye proviclel a; circulation in this s elotionanalogous to that of V; the cross cl-runr jst atioiiary bOilGrf Whichhas fproved itself capable of operating satisfactorily athigh f[overload ratings and; of responiing quick-ly "to extreme "fluctuationsin load, suoh'as are encountered 1nAl0o'o'm0t1Ve practice.

V n 1 l The "fire "box unit j ust desor'iloecl is' olosedinan-outer'ca'sing or main shellf22,

Whiiih is carri'ed torward as, shown in Figl ,ure 1 and {housestheisupenhefater; and the "fire tube evaporating 'unitsasjvell asftheleeoi'ion'iizer. f 4 Ii 1 The superheater unitjfis located justffonSta-relief theffire box "unit and will ibe Cleff sorib'ed in detail-later.

"ITl-'1'e fire tube evaporating unit, \yhieh ,prov'ides the main Waterstoring capacity oft-he ,25Ylooomotive, is primarily designedft'oWithfs'tandhig'h operating pressures and inplace oif theu sual singledrum of large diameter have substituted'a number of small di'aml V eterdrums so arranged as to utlllze to the gol naxiipum extent the clearance.s'pace' ayail 'ahle As ill begnoterl from Figure 2 the I Cross "sectionof the locomotive at this point is substantially rectangular,thisshapeper- ',initting the 'use of a larger seot'ional area i-itithin'given Clearance limits than is possible @With theuse'ofa cylindriealshell. In the embodiment illustrated]: have shown nine ijtweenthesedrumsfand between the outer clrums andthemain' boilershellh22occupiedbye, nurn bfefrof siinilardrunis 24of smaller diaineter; although'itisto be understood that the nu'mber and relative positions "of the 1 farmsemploye'cli may he m d without de- 1 $1J'artingfromtheseope of myinvention;

ftheuse of these smalltliame'ter drumslliam.

ab le to provide a fire tube evaporatingQ unit capable of withstandingthe extremely high I t v 'iopeliating pressures contemplated, without a'using'drum Walls of a thickness greater than normal; that is to'say,athioknessiof one "inch or-le'ss. I prefer-to use drun 's, the

I cylinolrical she-user which areformi d ot seam less drawn and therebyavoidthe f Q JIffdesired, thespaoes'l etween theexteriors oftheflseveraldruinsimay be blockecloff hy suitable refraetory' bafiles, i n which'case" all so o-f" the? combustion 'gases fwil'llie-forced through thefire tubes; the spaces may he left A j open; in which "case aportionofitlre come t ibustionfgases will passbetween'the drums i andmake fusefu'l evaporating surface the 6:; exterior surfaces thereof,".or .a portion only disea'nis to the eombusti'on the radiant-heat froWherethe pace islarge'enoug hinseotioiiah 1 e boil Whioh;ashmayibe seenfrom elFigu-re'l;-=are" ngo'f fse't relation to ecjq moaatethe"insjertion otthe nipples in the cylindrical V shell portionsjthefedf. VAijsimilar 'tran sveij e st am and Water drum "ill dl ntedt qufinae-themainboiler shell as theforwardend of "the fire tube?clrums, ,eaehofwhiehis in T v turn conneoted to" the ,clruini 28f lojy h1eans (if I a secondsetof nipples 2 9,, theliiorward ends of the'dr'ums beingofis'et'iin thesamemang 28 andBO areconnected bya series "of water;

circulators 3'1, and steam" circulato'ifs 132; go

omeirsi 1 i c ct ph fiend. of he 7 wiser space 071 'th' i drum; :30 withthe." drun1"26;"$ I n lt Will it I geneF-ating'unit a leo njt-inujousoirculatijonfhas been, proyi'clecl for. The nip1 3les29{Carry the steamand atei.'cl1'se1iarge fromfthe generating,drmn tothe-transversesteamjand Water drum 28;.Whichfproxiiclesj the'necessa'ry liberatingsufrfacefthe 'steam separated i n j gflol drum 28jihei'ng carried io'veiito "the stea space of drum 30-throughethefoireulatoi s32, e

Where further 7 separation; Inlay} take {ii-ace;

and 'fro n ith'erefbeing diseh'argedjtonthe.su- I perheater. return'Water circulation ;,,-1 05 provided from ,gdmm 28, through the circutheiswer water drunrQG', which s-ervesto nippl s 73 V supply theevaporating drums the 510 to the fire box u'i'ii't" by means i of; aseries 1 of.

ertical tube's'j l' connecting the flowertfan'sverse water drum 26-withft'hefwatermspace llfi of 'thetransvers'e gram 1 These wees serve asequalizers hetweentlietwo units-end neare the means f r-suppl ingreed YW t' ri' he mb xi i -g lnzi i i e m i b seen f om Fi res 11 v t e s?tubesiform a 'Wat'er screen; across the coriilou'se tion'g'as'outletllli {o f the beginning I These tub'es will generate st'ejaminhoonsitlerable QuantityQaS theyflare' subjected! namely ,w a

at approi'iilnately firebox temperature, and

theirdiseharge into the drum 1'81Willbfel'i ery violent. Inorder]thereforetoi provideq a ady Jfl w r. r eve-1 9 5191,

"t'oji thefull yolumefof the" combustion gasses curved bafile 35 isprovided in drum 18 over said nipples, the baflle, however, notextending to the; ends of the drum. Water flowing to the nipples 19.passes underthis bafiie from the comparatively quiet ends of the drumand. a-fsteady supply ofjwater to the nipples and downfiow headers isthus assured. v I

In order that dry steam may be taken oif from the drum 18, a secondbaifle 36 is placed across the top of the drum above the circulators 20and below the steam offtake 37, this second baflie also terminating atthe drum heads short of the ends of the drum so that the discharge fromthe circulators and the tubes is prevented from reaching the steamofltake 37 directly, thesteam flowing to the otftake by way of'the.spaces at the ends of the dru As indicated in Figure 1 a considerablespace is provided between the'vertical tubes 34 and the rear ends of thefiretube evaporating drums 23 and 24, this space being enclosed by themain boiler shell 22 and forming a location for the superheater unit.The

steam offtake 37 from the firebox unit and the offtake 38from thefiretube unit are connected by means of flexible expansion oints 39, inwhich may be incorporated steam separators, to a commonsuper'heaterinlet member 40 having twobranch arms which connect respectively to thesuperheater inlet headers 41 and 42. Headers 41 and 42 are respectivelyconnected by tubular superheater elements 43 and 44 to a common outletheader 45, from which the steam is delivered to the usual throttleindicated at-46 The main boiler shell 22 is carried for- Ward from thefire-tube evaporating unit to form a smoke-box section 'invwhich thereis mounted transversely thereof an economizer,

- indicated generally at 47, which delivers the boiler feed Waterthrough the conduit 48 to the Water space'of the dru'm28. The mainboiler shell is recessed at eitherside of. the economizer and in therecesses so provided there are disposed a series of vertical settlingtanks 49 and 50 at either side of the boiler. An exhaust steam feedwater heater 51. is provided which delivers pre-heated feed waterthrough the left hand series of settling tanks 49 to the economizer.From the economizer the feed water, which has been raised toapproximately boiler temper- 1 ature, is delivered through the right"hand series of settling tanks 50 and conduit 48 to the boiler drum28.The economizer shown here, together with the settling tanks andarrangement thereof, is illustrated in detall in my copendingapplication Serial am -3,538, filedJ'anuary 19, 192 5, to whichreference may be had for a more detailed description.

' Referring now to Figure 4, I have shown a modified form of'boiler'which in the main is similar in construction and arrangement to theform shown in Figure 1 but which is adapted to accommodate a difierentform of economizeri In this formthe firebox'and.

superheater units are identical with those already described andtherefore need not be described in detail; The firetube unit is alsosimilar in general arrangement to the form shown in Figure 1 but iscomposed entirely of drums .23" which are somewhat longer than thecorresponding drums shown in Figure 1 and which occupy'the major portionof the smoke-box section. In this form, where the smaller drums areomitted, comparatively large spaces are left between the drums, whichare utilized for the accomodation of. atubular economizer. In this formof (construction, pre-heated feed water is delivered from the feed waterheater 51 through the conduit 52 to an economizer header 53 which issuitably partitioned to cause a series flow of feed water through thetubular economizer units 54 arranged in the a inter-drum spaces formedby the lower rows of drums. After traversing the first series ofelements 54, the feed water passes through the nipple 55 to a secondheader 53, similar to header 53, and which directs the feed waterserially through a second series of elements 54 arranged in the inter-.drum'space between the upper rows of drums] Nipple 56 connects; theoutlet of header 53 with a third header 56 which directs, the feed waterthrough a third series of economizer elements 54" located between theuppermost drums and the main boiler shell. The feed water is dischargedfrom header 56'through the conduit 57 to the water space ofthe forwardboiler drum 28'. From the foregoing description it may readily be'seenthat I have provided a locomotive boiler Whichis materially difierentfrom the usual form, over which it possesses substantial "advantagesWhich'may be briefly summarized as followsz,

I am enabled, because ofthe water tube construction of the firebox unitemployed, to provide a firebox and combustion space of greater volumethan is usually the case This results in improved combustioncondiprinciples of boiler construction and with v existing shopfacilities.

i [as moms;

time, a better heat transfer rate due to the large arealaof heating.,surface exposed to idlrect kradiationfrom the fire, and adesiriableloWering of the temperature of the .coinbustlon gases beforetheirfexit from the combustion chamber.

cause ofthe large grate. area Which it ispossilo'le to 're nployy agreater combustion rate :JllElYgbQ maintained rtv ithout theintroduction fze'xcessive rdra'fit .and cinder losses; I V ob stainrtheregularaanel rapid water circulation ot-the :most .approyedtype of,Wfiillflftllbfi i boilers, gwiththe consequentflincrease in the ratesofevaporation and. furthermore because ofthe rom of my :firebox unit Ihave ayailtablesteani, generating means hich-is pecujil-iarly adapted to:ineet the extreme -fiuctuat e 1 ng loads encountered inlocomotivepractice.

' l By the construction and arrangement of :theifiie tube evaporatingunit I take adtan- --tageof-the full sectional area, available for malocomotive,- which is considerably. greater .than :can be utilized Withthe ordinary ;cy-'

"lind-rical formxof boiler shell. This presents afree gas area greatlyin'excess of that usually availabla resulting in a greater possibleboiler capacity. By using this section of the 'boiler for a fire tubeevaporating unit -only, "I am ableto provide in this space fire tubeevaporating drums in which are used a large number 'oflclosely spaced,small -diameter fire tubes,giving alarge area of "heating surface perunit of boiler length and "thereby "obtaining the required amount ofheating surface with a unit of comparatively e short length, I obtain an-improved evapo- "ratil g rate in the fire tube unit by thearlgrangement of the se -er'algelements in such v 'manner that adefinite :and regular Water 140 circulation therethrough is obtained,analoffi're :tube unit furthermore providesva large gous to that of aater tube boiler. The

storage capacity' and forms a reservoir, of

water heated to the evaporating temperature available as feed to thefirebox unit, which is called uponio add only the heat of Vapori- 7 .Jzation thereto in' order to produce the steam necessary to meetincreases in load.

I "f By p'lacing the superheater unit between, the ifirebox unit-and thefire tube unit; and

, theeconomi zer forward of the latter unit t jlobtain a waterand steamfioW through the 5 ibo'ile'r counter to that of the gases, andthereby'cbtain the most eflicientrate :of heat transfer. Thesuperheaterunit is placed in a high temperature gas zone Where the requireddegreeof s uperheat may b'e' obtained v with a minimum amount of -supei-"heatiiig' surface. This results not only in a reduction "inyt'hepressuredrop through the super 7' heater,- due to the'i short elementsemployed,

but also in a reductiouin the obstruction tothe free gas flow throughthe boiler 'be-v cause-01E; the space occupied by the superiheate'relements. I further obtain the ad- Furthermore, be-

vantages of a mixedradiant anal-c mment typev superheater, as swi h Ihea'sute heate arrangemen I employ the ele nts dissent are exposed notonly to the gases inweontaet therewith but also to direct" radian heatfrom the firebox unit. u the more he amount-oi radiant heat -;reacl iingthe f heater elements may be, readilycontr Because of the short regattasas e w cu to materially increase; the: o er Qn'gfif ciency by reducingthe temperatur combustion? gases to .a;point;near--boiler tem peraturebefore theylireach the stack 1 The provision :ofthe two. series ofsefutlingi f tanks; assurestheeliminatiohof s bstan tially all feed Waterimpurities: before the feed .Waterenters the boiler 1 and because of 5the re-circulation of the boiler. ater in the by the arrangement andspacingco fthe meal]; 5 tube scrjeen'interposcdfbetw. en' the fireboxand su'perheaterunits. E"

unit possible :Wi'th any}iconstrilctimlt- 0 able Within a permissibleaoverau .-%b it r length toobtain' a,.-10n -;a dlfunohst ucted smoke-boxs ctiong uitable for t e eccqm modation of anteconoiiiizer of sufii firetube evaporating section any/impurities I which may ass through;the""settling chamJ- l bers will be c eposited in the tfire tubesech blbefore reaching the fire: boX'. ni 0 .wh fih e9 a substantially pure-fe'ed'water is Ealwa sq supplied This latter feature' is important; i

astherate ofevaporationin=thefire boxfunit is very-rapidand this;toge ther with the af treme gas temperature obtaining inthisunlt,

a stir-- makes it desirablerthat the evapomt faces thereof be-kept astree, from possible. I p a What I clainiiszE 1; A locomotive boilercomprising l serially 4 arranged with respect. to the; gas

e ve

, a. 7.. i rality .ot commun cat ng evaporat ng units ering a steamandwaterfmixture froinc the generating? elements and; thereto.

2. A locomotive boiler comprising atpri marry water tube evaporating.:lllllt hay ng a1 fi rning water V p p I Y complete Water circulation-Within' 'i tself,fa

secondary firevtubeievaporating unit, said secondary unit having a con'pletezwater 77 circulation independenttotlthat of said pr -f a I maryunityand connectionfbejtween saidigizs units whereby-saidsecondaryunitfurn shes' the feed Water supplied .to said primary unit. a

1 8. locomotive boilei ic'omprisinga w niary Water tube evaporat ngumthaninga? 'icomplete'watcr circulation withinitself, a secondary firetube evaporating unit, sa1d secondary unit having'a complete watercircul'ation independent of that of said primary unit, aconn'ect1on'between'sa1d LII1liLSWliBI'Q by said secondary unitfurnishes the feed Water supplied to sa1d primary unit, and a commonsteam offtake from said units.

'4. A locomotive boiler comprising a primary Water tube evaporating unithaving a I a complete water circulation Within itself, a

secondary fire tube evaporatingunit, said secondary unit having acomplete water circulation 1ndependent of that of said pr1- mary unit,and a feed water connection from said secondary to said primary unit, acom- 'mon steam oiftake from-said units, and a superheater locatedbetween sa d units and connected to said steam offtake.

51A locomotiveboiler comprising a primary'water tube evaporating unithaving a complete water circulation within itself, a secondary fire tubeevaporating unit, said secondary unit having a complete Watercirculation independent of that of said primary unit, a common steamolftake from said units, and a superheater located be- A with aprimarywater tube evaporating unitunits. If

tween said units and connected to said olftake.

6. In a locomotive boiler, the combination the tubes of which form thewalls of a furnace and combustion space and having a definite andcomplete water circulation within itself, of a secondary firetubeevaporating unit, having a complete Water circulation independent ofsaid primary unit and through which the combustion gases discharged fromsaid primary unit pass,and means for abstrac'ting additional heatfromthe combustion gases after the major portion of their heat has beengiven up to the evaporating 7.111 a locomotive'boiler, the combinationwlth-a'primary water tube evaporatingunlt the tubesof whichforni theWalls of a fur- -nace' and combustion space, and having a definiteandcomplete water circulation within itself; of a secondary firet-ubeevaporating unit having a complete Watercirculation independent of saidprimary unit and through -Wl'liCli the combustion gases discharged fromsaid primary unit pass, and a super-heater located'between sa1d units.

8. In a locomotive boiler, the combination of a primary water tubeevaporating unit 1 the tubes of which form the walls of a furnace'andcombustion space and having a definite and "complete water circulationWithin itself, a secondary firetube evaporating unit,

having a complete water'circulation inde- 1 pendent of sa1d primary unitand through,

v Which the combustion gases discharged from said primary; unit pass, asuperheater locatedbetween saldumts, and means for abstractingadditional heat 'froni the combustion gasesv after themajor portion oftheir heat has been given up to the evaporating units. i

9. A locomotive boilerrc'omprising, in combination, a Water tube primaryevaporating unit having a small'water volume and a definite and'complete 'water circulation within itself, the tubes ,of said'unitforming the walls of a furnace and combustion chamber,

a secondary firetubeevaporating unit having a large water volumeandadefinite and complete water circulation independentof sa1d primary unit,and aavater feeding connection fromf said secondary'to said primaryunit, whereby said secondary unit provides 'for'both units .a largereserveof water at evaporating temperatrire to meet fluctuating steamdemands.

10. A locomotive boiler. comprising, in combination, a prmiary watertube evaporating unit having asmall water volume and a definite andcompletev Water circulation within itself, the tubes "ofsa-id unitforming the walls of a furnace and combustion chamber, a secondaryfiretube evaporating unlt having a large Water volume and a definite andcomplete water circulation independent of sa1d primary unit, a Waterconnection between said units, and an economizer delivera secondaryfiretube evaporating unit having a large volume and a definite andcomplete tween said units let.

12. A locomotive boiler comprising, in combination, aprimarywater tubeevaporating unit having a small Water volume and a definite and completeWatercirculation within itself, the tubes of Said unit forming the watercirculation independent of said pri- 7 marygunit, a common 'steam outletconnect ing said units, and a superheater located beand connected tosaid out walls ofa furnace andcombustionrchamber,

a secondary 'firetube. evaporating unit having alargewater volume andadefinite and complete water circulation independent of saidprimaryunit, a-water connection between said. units, a common steam;outlet connecting said units, a superheater located between saidunits-and connected to said outlet, and an" jeconomizer delivering waterat substantially evaporating; temperature to :said secondary evaporatingunit.

15. In 7 a ,Watertube locomotive firebox unit, in combination, upflowand downflow headers, a steam'and water drum above said downflowheaders, v ,clrculators connectingsaid'dr-uni with; said downfl'owheaders, circulator-s connecting said" drum with said up flowheaders,and apluralityofhorizontally inclined tubes," connecting- Ysaiddownflow tosaid upflow headers and i'fo'rming the. side walls ofsaid fire-box, said: tubes bei-n X- v posed for the major portion oftheir length to radiant heat generated in the fire-box.

"'14P. 111 a ater tube loconiotixre fireboX unit, in -combmanen, upflowand" do nfloW headers, a steam and Water 'dr uin above; I said'downflow. headers, ci-rculators connect, A ingfsai'd druni-"Withsaiddownflowgheaders ici' rcu-latorsconnectin said drum" Withsaid upflowheaders, a plurality of horizontally 'lators,

1 '15; In a watertubelocomotive firebox down-flow headers, horizontallyunit, the combination with upfiow' and lnelined side-'walltubes'connecting said headers, a

1 stea rnand ater drum, and eir culators con-- necting said druin with'said 'downflow necting 'said last named headersheaders, of circulator'sconnectingsaid: up-

flow headers With said drum, {said circu lators carryingheaders intermedate their ends; 1a-nd supple1nental side Wall tubes condoWnfloW headers.

unit, a; sidewall construction comprising,

' 1 combinatioma v ertie'a'lupflowheaderjand a, ire'rtiizaldownfl'oxtheader, a steam and I -Water drulnlabove said doWn'fi'oW header, a

fi'l c v i,

' downflow header, a-plurahtyof horizontalcirculator connecting saiddrumto said 31y inclined sidewall tubes conneoting said headers,- asubstantially 'liorizontal circulator t connecting said upflow headerswith said drum and means rovidin additional water cooled side- Wallsurface between said side wallitubes and said last named c ireulator.

v "jfire box unit comprising horizontally. in-Q j 17 I In i a locomotiveboiler, a Water tube cli'ned side wall' t ub'es, outer tront and-rear'headers"connected'by said side Wall tubes,

intermediate tront and rearheaders connected to said' outer headers and;forming f'ro'nt and rear'Wa-ter W21Jll'S,'LI1d 1OO'ff tubes connected tosaidinterm'ediat'e headers, some "of -said intermediate front headersbeing. spaced apart and-providing a. combustion gas outletthere-between. a I, 18]. In a locomotive boiler,*aa;water tube fire-box"unit Comprising: horizontally inicli'ned sidewa-l ht'ubes, outer frontan'd'rear "headers connected by said? side Wallttubes, o intermediatefront, and-rear headers conn ected* to said outer headers and" formingfr'onfi'and rear Water Witllfl someoi: said mediate I front headersbeing: space/d apart .porte'd: on said roof"tubesj anobdirecting theCQlDbllStlOIl gasestoward sai 16.]In' a Water tubelocomotivezfirebox"said outletfand said superheater. v a

l '23. In a loconiotive; :boileig the Combineintermediate frontj headeisflbel spaced? apart and providing a eembustion gas out 7 letthere-between, roof tubesfoonneetiiig said int'ermediatefront and rear]headers above said outlet," and spacedarchtubes connect ing' saidintermediate front and rear head 19.111 a locoinotive boiler, a' watetribe J I fire-box] unit comprising {honi zontally-l n clined side alltubes,- outer front and rear headers I connected by said side walltubes, in-

'terniediate front and rearheaders {connected to said outer headers andforming the from? I and reanwater Walls, some of -sai'djinter and:--providing a "combustion gas outlet 1 t'here'between, roof tubes sconnecti'ng said intermediate front and yrear headers above said outlet,"and a refractory roof bafiie? sup n outlet; 20. In alocoinotive'bioi-l'er, Water: tube fire-box unit comprising fhorizontally in clined side wall 'tub'e's, outer front andlrear I i I Iheaders connected 'said side wallf tnbes; :i' intermediate ,front "andrear: I headens' con nected to said outer headers and li' oiming front aand rear "Water- 1 Walls, some of said intermediate, frontheaders beingls'pacedT apart and 'prouidingia combustion: gas out-1 935 letthere-between, roof tubesconnectinggdtidfintermediate front -andrearfhead'ers above with said c said outlet, asteain and Water di uminount -fl ed above saidfront' headers, and cinculators connecting saiddrum with said front and i rearheaders." 21'. In a locoinoti ve'{boiler-,rin jeoinbin tion," a primary evaporating-unit havin a combustionqga's'outlet therefrom; a second ary evaporating unit fthro-ugh which thecombustion gases from said primary nnit pass, a superheaterlocatedbetweenv said units l and extendingacross said outlet, and J aconnection between: the vv-atei' spacesof said Qunits, said'conneotiompassi-ng between said: combustion gas-outlejt' and: saidsupei Y heaterand forming, atherlnal screen foritlie latter; 1 :7 f 1 iv 22. In a locomotive boiler-, inwcombina tion, a primary evaporatingunit-having a combustiongas outlet therefrom and a steam and Water drumlocated above: said outlet, a secondary evaporatinglunitthrough whichthe combustiongases from s'aid priinary unit pass andhaving a waterdrumgloeated E20 below said outlet, a su perhoaten 'located 'betweensaidunits, and a pl'urality; ot' tubes K connecting said" aterdrum withsaid steam and Water drum, said tube's passing "between tion of aprimary eyaporating unit: having j complete water circulation: "with n;itself, a secondary evaporatmgiumt comprisingia plufalit'y ofi, fire,-tubes dr ims,-, serially. eon 30' nectedelements connecting the endportions of said drums to forma closed water circulating path withinsaid secondary unit in which the flow is longitudinal of said drums,some of said elements providing the steam liberating surface and steamoutlet for said drums, serially connected elements connect ing the endportions of said drums to form a closed water circulating path withinthe unit in which the flow is longitudinal of said drums, said elementsforming the sole of communication between said drums and providing thesteam liberating surfaceancl steam outlet for the unit.

25. In a locomotive boiler, an evaporating unit comprising a pluralityof parallel fire tube evaporating drums, a water drum connected to oneend of each of said'evaporating drums, a steam and water drum connectedto the opposite end of each of said evaporating drums, whereby a directlongitudinal flow through said drums is imposed, and

means of returning water from said steam and water drum to said waterdrum.

' 26. In a locomotive boiler, an evaporating unitcomprising a pluralityof parallel fire tube evaporating drums, a water drum con nected to oneend of each of said evaporating drums and supplying water thereto, asteam and water drum, connections delivering the discharge from each ofsaid evaporating drums to said steam and water drum, a feed water inletin said steam andwater drum, and means for conveying the feed water andthe water discharged from said evaporating drums to said water drum.

. 27. In a locomotive boiler, an evaporating unit comprising apluralityof parallel. fire tube evaporating drums, a water drum connected to oneend of each of said evaporating drums, a steam and water drum connectedto the other end of each of said evapcrating drums, a second steam andwater drum, steam and water circulators connecting said steam and waterdrums, downcomers' connecting said second steam and water drum to saidwater drum, and a steam outlet in said second steam and water drum.

28. In a locomotive boiler, the combination, with a'main shell throughwhich the combustion gases make a single longitudinal pass; of aplurality of small diameter fire tube evaporating drums locatedlongitudinally of said shell and occupying substantially the fullsectional outline of said shell, and additional heat absorbing meanslocated between said drums, and substantially filling tion with a mainshell through which the combustion gases make a single longitudinalpass; of a plurality of fire tube evaporating drums locatedlongitudinally of said shell and occupying substantially the full crosssectional outline thereof, and additional heat absorbing means locatedin the spaces between said drums, said means comprising a second seriesof fire tube evaporating drums substantially smaller in diameter thansaid first named drums.

30, In a locomotive. boiler, the combina tion, with a main shell throughwhich the combustion gases make a single longitudinal pass; of anevaporating unit comprising a plurality of small diameter fire tubedrums located longitudinally of said shell and occupying substantiallythe full cross sectional area thereof, all of said drums lying whollybelow tliewater'lever in said boiler.

31. In a locomotive boiler, the combination, with a main boiler shellthrough which the combustion gases make av single longitudinal pass; ofa plurality of small diameter fire tube drums located longitudinally ofsaid shell and occupying substantially the full cross sectional areathereof, serially connected elements forming with said drums a closedwater circulating path in which the fiow is longitudinal of said drums,said elements'including nipples connected to said drums,-and said drumsbeing offset longitudinally of each other to permit said nipples to beconnectedto the sides of sald drums. v

32. A locomotive boiler comprising a primary, water tube evaporatingunit having a complete water circulation within tself a secondaryfire-tube evaporating unit, sa1d secondary unit having a complete watercirculation independent of that of said primary unit, and meansconnecting said units below the normal water levels thereof to maintaina substantially common water level in the twounits; A 33. A locomotiveboiler comprising a primary water tube evaporating unit having acomplete water circulation withln 1tself, a secondary fire tubeevaporatmg un1t,-sa 1d secondary unit havinga complete water circulationindependent-of that of sa1d primary unit, and a connection between sa1dunits below the normal water levels therem, said connection serving tosupply feed water from the secondary to the primary unltby gravity, andto maintain a substantially common water level in the two 'unlts.

34. In a locomotive boiler, the combination of a primary evaporating,unit havmg a complete water circulation wlthln itself and a steamoutlet, a secondary evaporatingunit comprising a plurality of fire-tubedrums, serially connected elements connecting the end portions of saiddrums to form a closed water circulating path w tlnn sa1d 1 1,764,431 fr f j f 9f:

secondary unitin whichthe flow is longitudinal of said drums, some ofsaid elements providing the steam liberating surface and V I steamontletfor said secondary unit, a super- 'heater located between saidunit-sand cone "w nected' to said outlet, and a connectionjbe tween oneof said elements-andsaid primary 7 'unitWherebyWater is siqoplied' tosaid prij 1 l rnary unit from said secondary unit." 7 35.: Inla]locomotive boilenan vaporatingunit comprising a pluralit of fire-tube fdrums, arranged in p'a'i'allel with respect tov ithedgas flow throughthe boiler, serially con 7 v ne'cted elements connecting the end portionI "jof said drums to form a closedcwatercircu- ,lating path Within theunit in which the flow is longitudinal ofsaid drums, said elements 7"providingthe steamliberating surface, and steam o'utletfor'theunit. v e36 In a locomotive boiler, an evaporati P flingnnit comprising aplurality of fire'tube r I ixdruins, arranged in parallel with respectto 'Q the gas flow through the boiler, serially connected elementsconnecting the end portions ofsaid drums to form a closed Water circus'lating path Within the unit inwhich the flow 1; is longitudinal ofsaiddruins, one of said elem'ents providing a steaniliberatingsurface,and others of said. elements connecting each of said drums directly tosaid one i CARL A. w BRANDT. v

c element-

